Monitoring elastic cluster rebalancing

Vertica includes system tables that can be used to monitor the rebalance status of an elastic cluster and gain general insight to the status of elastic cluster on your nodes.

• REBALANCE_TABLE_STATUS provides general information about a rebalance. It shows, for each table, the amount of data that has been separated, the amount that is currently being separated, and the amount to be separated. It also shows the amount of data transferred, the amount that is currently being transferred, and the remaining amount to be transferred (or an estimate if storage is not separated).

  Note

  If multiple rebalance methods were used for a single table (for example, the table has unsegmented and segmented projections), the table may appear multiple times - once for each rebalance method.

• REBALANCE_PROJECTION_STATUS can be used to gain more insight into the details for a particular projection that is being rebalanced. It provides the same type of information as above, but in terms of a projection instead of a table.

In each table, the columns SEPARATED_PERCENT and TRANSFERRED_PERCENTcan be used to determine overall progress.

Historical rebalance information

Historical information about work completed is retained, so query with the table column IS_LATEST to restrict output to only the most recent or current rebalance activity. Historical data may include information about dropped projections or tables. If a table or projection has been dropped and information about the anchor table is not available, then NULL is displayed for the table ID and <unknown> for table name. Information on dropped tables is still useful, for example, in providing justification for the duration of a task.